In flight, a helicopter generates and stores a charge of static electricity. Since the advent of helicopter external loading operations, helicopter support team personnel have been subjected to severe shock from this static electricity and the danger of being crushed between the aircraft and the external load during the hook-up phase of the cargo handling operation. Various wands, shepherd crooks and other devices have been utilized in an attempt to eliminate these hazards, but none have been completely satisfactory.
One method used by the armed forces for external helicopter loading requires the ground personnel to make the hook-up to the helicopter by hand. In this maneuver, the becket end of the sling is hooked to the aircraft lifting hook by a man who stands astride the proposed load under the hovering helicopter. This operation subjects the man to a severe, static electric shock and the danger of being crushed between the aircraft and the external load.
Shipboard loading is even more dangerous since the loader must contend not only with the helicopters' vertical and horizontal movements, but also with the movement of the ship in the case when the hook-up is being made at sea. This added motion, coupled with the static electric shock, makes the hand held hook-up method of shipboard hook-ups even more hazardous.
U.S. Pat. No. 3,893,005 to Corbin is directed to a grounded pole for attaching a load-carrying sling to a helicopter which includes a hollow extension pole made from a non-conducting material, a hook-up head attached to one end of the pole and made from a conductive material and a grounding cable connectable at one end to a grounding rod and connected at the other end through the lower end of the pole to a metallic plug. A wire braid extends through the bore of the pole to connect the plug to the hook-up head so as to conduct to the ground any static electricity which may be transferred from the helicopter to the hook-up head. The hook-up head of U.S. Pat. No. 3,893,005 was designed specifically to accept a nylon web ring apex, or donut utilized in conjunction with 15,000 pound cargo slings.
Over the passage of time, improvements in sling material and design have produced various types of sling assemblies. With these new sling assemblies, new hook-up assemblies which use hook-up rings or apex shackle fittings have been developed. The newer hook-up assemblies are made of various sizes for different lifting capacities and are made of metal or nylon webbing.
Since the hook-up head of U.S. Pat. No. 3,893,005 was specifically designed for use with a particular nylon web ring, the hook-up head of this patent cannot be utilized with other assemblies such as cargo net hook-up rings or metal apex shackle type fittings.
Thus, a definite need exists for a device which can be utilized with a variety of hook-up assemblies, including cargo net hook-up rings or metal apex shackle type fittings of various sizes.